Method of inserting z-axis reinforcing fibers into a composite laminate

ABSTRACT

A method of inserting z-axis reinforcing fibers into a multi-layer composite laminate. Layers of material made up of z-axis fiber and y-axis fibers are automatically transported into a z-fiber deposition machine having a housing with upper and lower surfaces. Z-axis apertures are formed in the respective upper and lower surfaces. An elongated solid rod having a tapered front tip is aligned in close proximity to the aperture in the bottom surface. The rod is first rotated by a motor and then actuated upwardly completely through the thickness of the layer of x-y material by an actuator. A first hollow tube having a z-axis is axially aligned with the aperture in the top surface and a fiber bundle is threaded downwardly through a first hollow tube to a position adjacent its bottom end. The z-fiber deposition machine has structure to feed a predetermined length of the fiber bundle downwardly through the first hollow tube so that it follows the pathway in the x-y material formed by the rod which is now withdrawn downwardly through the aperture in the bottom wall. The z-axis fiber is thus deposited into the x-y material. The top end of the z-axis fiber is then severed and the x-y material is then advanced a predetermined distance to complete the cycle and is, thus, set to be repeated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation-in-part application of U.S.patent application Ser. No. 09/922,053 filed Aug. 2, 2001, which issuedas U.S. Pat. No. 6,645,333 on Nov. 11, 2003, and claims the priority ofprovisional patent application 60/281,838 filed Apr. 6, 2001 andprovisional patent application 60/293,939 filed May 29, 2001.

This invention was made with United States Government support underCooperative Agreement 70NANB8H4059 awarded by NIST. The United StatesGovernment has certain rights in the invention.

BACKGROUND OF THE INVENTION

The invention relates to a method of producing a composite material andmore specifically a process for incorporating z-axis fiber reinforcementinto x-y axis composite material.

Traditional composite materials are made up of resin matrix material anda quantity of 2-dimensional fibers, continuous in the x-y axisdirections, but laminated in layers to produce a material thickness.Composite material construction, wherein a fiber material such as glassfiber, carbon fiber, or aramid fiber is combined with a matrix material,such as thermoplastic or thermoset resins, is an example of atraditional 2-dimensional structure. The resulting structure is producedfrom “layering” of the 2-dimensional material (known as plies). Becausethe matrix is weaker in strength than the fiber (in many cases by atleast an order of magnitude), the failure mechanism of these compositeswhen test loaded toward their ultimate strength is a cracking orbuckling or separation of the matrix material. When this occurs, thecomposite is known to have delaminated, or the layers of fiber materialhave separated.

Attempts have been made to lace or tie multiple layers of 2-dimensionalcomposite materials together with z-axis directional fibers which tieall of the layers together. By doing this, delamination can be delayedor eliminated. Some techniques that have been used include 3-D braiding,3-D weaving, and z-axis pinning. All of these methods have deficiencies,drawbacks and are expensive and labor intensive.

The Fusco et al U.S. Pat. No. 5,589,015 is directed to a method andsystem for inserting reinforcing pins in composite structure. Ultrasound energy is applied to the pins and pressure is appliedsimultaneously to insert the pins into the composite structure to jointwo laminates or reinforce a single composite structure.

The Childress U.S. Pat. No. 5,935,680 is directed to an interlacedz-axis pin sandwich structure that utilizes a plurality of z-axis pinsthat extend through the core and into each of the face sheets. The pinsare arranged in an interlaced configuration off-normal to provide crackresistance around fasteners for connecting the composite structure toother structural elements in aerospace applications.

The Boyce et al U.S. Pat. No. 4,808,461 discloses a translaminarreinforcement structure that utilizes z-axis reinforcing elements andthe method for driving these reinforcing elements into the compositestructure as it is subjected to an elevated temperature and decomposes.

The Campbell et al U.S. Pat. No. 5,789,061 discloses a stiffenerreinforced assembly and its method of manufacturing. The Boyce et alU.S. Pat. No. 5,667,859 also discloses the use of joining compositeparts by including reinforcing elements that pass through the thicknessof two composite adherents to be joined. The Campbell et al U.S. Pat.No. 5,827,383 also discloses a stiffener reinforcement assembly and itsmethod of manufacturing.

Other patents that teach the use of tow members that are encapsulatedwithin the foam core and which extend between the opposing face sheetsto form a combined composite structure are the Boyce et al U.S. Pat. No.5,624,622 and the Boyce et al U.S. Pat. No. 5,741,574. The Boyce et alU.S. Pat. No. 5,186,776 teaches a technique for translaminarreinforcement and the method includes heating and softening thecomposite laminates by ultrasonic energy and then inserting reinforcingfibers therein.

It is an object of the invention to provide a novel method of insertingan unstable reinforcing fiber into a composite laminate for z-axisreinforcement.

It is also an object of the invention to provide novel machinery forinserting an unstable z-axis reinforcing fiber into a compositelaminate.

It is another object of the invention to provide a new type of compositematerial with substantial z-axis fiber reinforcement.

It is a further object of the invention to provide a novel method forproducing layer quantities of 3-D bar stock, sheet and compositesandwich structure in a continuous, automated fashion.

SUMMARY OF THE INVENTION

The method of inserting an unstable reinforcing fiber into a compositelaminate for z-axis reinforcement of the laminate requires a z-axisfiber deposition material. The side plates of the chamber formed betweentop and bottom plates into which is fed x-y axis material. The sideplates of the chamber restrict the edges of x-y axis material. Therewould be multiple laterally spaced z-axis fiber deposition machines sothat multiple z-axis fibers could be deposited into the x-y axismaterial at the same time. Each would have its own respective aperturein the top plate and the bottom plate and these would be aligned. Beloweach aperture in the bottom plate is an elongated solid rod having atapered front tip. This rod is known as the “pathway deposition probe”(PDP). The PDP is rotated by a motor and then actuated upwardly throughthe aperture in the bottom plate, the x-y axis material and the aperturein the top plate. Mounted above each aperture in the top plate is amovable hollow tube whose initial position has its bottom end slightlyinserted into the aperture in the top plate. Z-axis fiber bundles arecontained on stationary rolls and are free to be drawn from the rollscontinuously. The front end of each z-axis fiber bundle is threadeddownwardly through one of the movable hollow tubes to a positionadjacent its bottom end. There would be structure to resupply apredetermined length of z-axis fiber bundle to each movable hollow tubeas a new length is needed.

After the PDP has been actuated upwardly to its upper most position, itis then retracted downwardly to its initial position and simultaneously,the movable hollow tube would travel downwardly through the hole createdin the x-y axis material. While this is happening, the tip of the PDPwould remain inserted into the bottom end of the movable hollow tube toinsure a smooth entry of the hollow tube through the aperture in the x-yaxis material created by the PDP. Each z-axis fiber deposition unit hasa mechanism for preventing withdraw of z-axis fiber from the x-y axismaterial when the movable hollow tube is withdrawn upwardly. Once themovable hollow tube has been raised to its upper position, the top endof z-axis fiber that has been inserted into the x-y axis material issevered. This would complete a whole cycle. Simultaneously, across thewidth of the housing each of the other z-axis fiber deposition unitswould have completed their cycle. Next, the x-y axis material is steppedforwardly to provide a new position for the z-axis fibers to bedeposited. Alternatively, the method could provide structure forstepping the housing rearwardly instead of stepping forwardly the x-yaxis composite material.

After the x-y axis material has had the z-axis fibers deposited therein,it travels forwardly to a pultrusion die. Here the heated die cures thecomposite material of the plies and it exits the dies as a cured 3-Dfiber composite material. The material is pulled from the diecontinuously by the alternate gripping edges of multiple grippers thatare attached to motion control hydraulic cylinders.

It should be noted, the x-y material may be impregnated with resin priorto the insertion of 3-D fiber, may be impregnated with resin after theinsertion of 3-D fiber, or may be impregnated with “pre-preg” resin atthe factory where the x-y material was made and/or the 3-D fibermaterial was made. In the later case, no resin impregnation would beneeded in the process, either before or after the insertion of the 3-Dfiber material.

Another aspect of the invention involves a method of inserting a z-axisreinforcing fiber into a composite laminate for z-axis reinforcement ofthe composite laminate. The method includes providing at least one layerof material made up of x-axis fibers and y-axis fibers prior toincorporation of a z-axis reinforcing fiber into the at least one layerof material; the at least one layer having a top surface, a bottomsurface and a predetermined thickness; providing an elongated pathwaydeposition device having a front tip, a shank portion, a rear end and az-axis and positioning the front tip of the pathway deposition device inclose proximity to one of the top or bottom surfaces of the at least onelayer of material; providing an elongated moveable z-axis fiberinsertion element having a front end, a rear end, an inner wall surfaceand a z-axis; positioning the front end of the moveable z-axis fiberinsertion element in close proximity to the other of the top or bottomsurfaces of the at least one layer of material; providing a z-axisreinforcing fiber bundle having a front end and inserting the front endof the z-axis reinforcing fiber bundle into the rear end of the moveablez-axis fiber insertion element until it travels substantially to thefront end of the moveable z-axis fiber insertion element; inserting thepathway deposition device into and through the at least one layer ofmaterial a predetermined distance; temporarily securing the z-axisreinforcing fiber bundle to the inner wall of the z-axis fiber insertionelement so that the z-axis reinforcing fiber bundle will move with thez-axis fiber insertion element; moving the z-axis fiber insertionelement in the z-axis direction until the front end of the z-axis fiberinsertion element meets with the tip of the pathway deposition device;moving the z-axis fiber insertion element and the z-axis reinforcingfiber bundle secured thereto through the entire thickness of the atleast one layer of material while at the same time withdrawing thepathway deposition device from the at least one layer of material;unsecuring the z-axis reinforcing fiber bundle from the inner wall ofthe z-axis fiber insertion element and then withdrawing the z-axis fiberinsertion element from the at least one layer of material, thus causingthe z-axis reinforcing fiber bundle to remain within the at least onelayer of material as the z-axis fiber insertion element is withdrawn;and severing the z-axis reinforcing fiber that is within the at leastone layer of material from the z-axis reinforcing fiber bundle.

Another aspect of the invention involves a method of providing a z-axisreinforcing fiber into a composite laminate for z-axis reinforcement ofthe composite laminate. The method includes providing at least one layerof material made up of x-axis fibers and y-axis fibers prior toincorporation of a z-axis reinforcing fiber into the at least one layerof material; the at least one layer having a top surface, a bottomsurface and a predetermined thickness; providing an elongated pathwaydeposition device having a front tip, a shank portion, a rear end and az-axis and providing the front tip of the pathway deposition device inclose proximity to one of the top or bottom surfaces of the at least onelayer of material; providing an elongated z-axis fiber insertion elementhaving a front end, a rear end, an inner wall surface and a z-axis andproviding the front end of the moveable z-axis fiber insertion elementin close proximity to the other of the top or bottom surfaces of the atleast one layer of material; providing a z-axis reinforcing fiber bundlehaving a front end and inserting the front end of the z-axis reinforcingfiber bundle into the rear end of the z-axis fiber insertion elementuntil it travels substantially to the front end of the z-axis fiberinsertion element; moving the at least one layer of material so that thepathway deposition device is provided into and through the at least onelayer of material a predetermined distance; moving at least one of thez-axis fiber insertion element and the pathway deposition device in thez-axis direction so that the front end of the z-axis fiber insertionelement and the tip of the pathway deposition device meet; moving the atleast one layer of material so that z-axis reinforcing fiber bundle andthe z-axis fiber insertion element are disposed through the entirethickness of the at least one layer of material; separating the z-axisfiber insertion element and the at least one layer of material, thuscausing the z-axis reinforcing fiber bundle to remain within the atleast one layer of material; and severing the z-axis reinforcing fiberthat is within the at least one layer of material from the z-axisreinforcing fiber bundle.

A further aspect of the invention involves a method of inserting az-axis reinforcing fiber into a composite laminate for z-axisreinforcement of the composite laminate. The method includes providingat least one layer of composite laminate material prior to incorporationof a z-axis reinforcing fiber into the at least one layer of material;the at least one layer having a top surface, a bottom surface and apredetermined thickness; providing an elongated pathway depositiondevice having a front tip, a body portion, a rear end and a z-axis andproviding the front tip of the pathway deposition device in closeproximity to one of the top or bottom surfaces of the at least one layerof material; providing an elongated moveable z-axis fiber insertionelement having a front end, a rear end, and a z-axis and providing thefront end of the moveable z-axis fiber insertion element in closeproximity to the other of the top or bottom surfaces of the at least onelayer of material; providing a z-axis reinforcing fiber bundle in themoveable z-axis fiber insertion element; inserting the pathwaydeposition device into and through the at least one layer of material apredetermined distance; moving at least one of the pathway depositiondevice and the z-axis fiber insertion element in the z-axis directionuntil the front end of the z-axis fiber insertion element meets with thetip of the pathway deposition device; moving the z-axis fiber insertionelement and the z-axis reinforcing fiber bundle through the entirethickness of the at least one layer of material while at the same timewithdrawing the pathway deposition device from the at least one layer ofmaterial; withdrawing the z-axis fiber insertion element from the atleast one layer of material, thus causing the z-axis reinforcing fiberbundle to remain within the at least one layer of material as the z-axisfiber insertion element is withdrawn; and severing the z-axisreinforcing fiber from the z-axis reinforcing fiber bundle.

A further aspect of the invention involves a method of inserting a z-xdirection reinforcing fiber or z-y direction reinforcing fiber(hereinafter z-x/y) into a composite laminate for z-x/y directionalreinforcement of the composite laminate. The method includes providingat least one layer of composite laminate material prior to incorporationof a z-x/y directional reinforcing fiber into the at least one layer ofmaterial; the at least one layer having a top surface, a bottom surfaceand a predetermined thickness; providing an elongated pathway depositiondevice oriented in a z-x/y direction and having a front tip, a bodyportion, a rear end and a z-x/y axis, providing the front tip of thepathway deposition device in close proximity to one of the top or bottomsurfaces of the at least one layer of material; providing an elongatedmoveable z-x/y directional fiber insertion element oriented in a z-x/ydirection and having a front end, a rear end, and a z-x/y axis,providing the front end of the moveable z-x/y axis fiber insertionelement in close proximity to the other of the top or bottom surfaces ofthe at least one layer of material; providing a z-x/y directionalreinforcing fiber bundle in the moveable z-x/y directional fiberinsertion element; inserting the pathway deposition device into andthrough the at least one layer of material a predetermined distance inthe z-x/y direction; moving at least one of the pathway depositiondevice and the z-x/y directional fiber insertion element in the z-x/ydirection until the front end of the z-x/y directional fiber insertionelement meets with the tip of the pathway deposition device; moving thez-x/y directional insertion element and the z-x/y directional fiberbundle through the entire thickness of the at least one layer ofmaterial while at the same time withdrawing the pathway depositiondevice from the at least one layer of material; withdrawing the z-x/ydirectional fiber insertion element from the at least one layer ofmaterial, thus causing the z-x/y directional reinforcing fiber bundle toremain within the at least one layer of material in the z-x/y directionas the z-x/y directional fiber insertion element is withdrawn; andsevering the z-x/y directional reinforcing fiber from the z-x/ydirectional reinforcing fiber bundle.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevation view of a z-axis fiber depositionunit;

FIG. 2 is a schematic side elevation view of a z-axis fiber depositionunits integrated with the pultrusion process;

FIG. 3 is a schematic side elevation view of a first alternativeembodiment of the z-axis fiber deposition unit;

FIG. 4 is a schematic partial cross section view illustrating a sandwichstructure having a core covered on its top and bottom surface withrespective skins formed of a x-y axis fiber material;

FIG. 5 is an enlarged schematic cross sectional view taken along lines5—5 of FIG. 4;

FIG. 6 is an enlarged schematic cross sectional view taken along lines6—6 of FIG. 5;

FIG. 7 is a schematic side elevation view of a z-axis fiber depositionunit integrated with the pultrusion process, where x-y material isimpregnated with resin after the insertion of 3-D fiber; and

FIG. 8 is a schematic side elevation view of another embodiment of fiberdeposition unit where fibers are deposited in the x-y composite materialin the z-x/y direction.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The method of inserting z-axis reinforcing fibers into a compositelaminate will now be described by referring to FIGS. 1–6 of thedrawings.

FIG. 1 shows a schematic elevation view of the novel z-axis fiberdeposition process and the associated machinery. The key element of onlyone z-axis fiber deposition unit is illustrated in this figure.Following a description of FIG. 1, a more detailed, expanded descriptionof multiple z-axis fiber deposition components will be discussed.

In FIG. 1, the cross section of a typical x-y axis material isidentified by numeral 30. Material 30 is a continuously travelinglaminate of x-y axis material. The direction of pultrusion and thecontinuous processing is defined as being in the x-axis direction and isleft-to-right. The y-axis direction is into the paper. The z-axisdirection is from top-to-bottom, through 3-D material 30. Only a fewlayers, or “plies” of x-y axis material 30 are shown, although clearly,additional layers could be shown. A single layer of material 30 is madeup of x-axis material and y-axis material, produced by other processesprior to incorporation into the z-axis fiber deposition process. Thisx-y axis material could be woven glass fiber or stitched glass fiber ora combination of each, or it could be mat or unidirectional woving, orcould be other fiber such as carbon or aramid. The material 30 may alsobe rovings.

Material 30 is contained in the z-axis direction by a chamber in thehousing shown only by the top and bottom plates 20 and 21, respectfully.The side plates of the housing, not shown, restrict the edges ofmaterial 30. Since there are multiple z-axis deposition points along they-axis, and since FIG. 1 shows only one of these points, the edges ofthe chamber in the containment housing and the x-y axis material are notshown. Plates 20 and 21 are pre-spaced such that a very compact set oflayers 30 are drawn through the housing, compressing the x-y axismaterial 30 to its nearly final z-axis directional compression prior toreceiving the z-axis fiber or entering the pultrusion die. Material 30may be impregnated with resin material and if thermoset, may be debulkedprior to entering the chamber in the containment housing defined byplates 20 and 21.

As stated earlier, material 30 could also be sandwich structure, withoutchanging the operation or process. As shown in FIG. 1, the material 30is a stack of layers of x-y axis fiber material, which, after depositionof the z-axis directional fiber, will be processed into thequasi-isotropic bar stock. If the material 30 is 1 inch thick (forexample), there might be 36 layers of x-y axis material making up the1-inch thickness. It would be a simple matter of construction tosubstitute for the middle layers of x-y axis material, a core material28, such as foam plastic, polyisocyanurate foam, honeycomb material, orbalsa wood (see FIG. 4–6). These core materials are low density and areused in sandwich structure construction. In this manner, material 30could have six layers of x-y axis material on the top, a core materialof 0.75 inches in thickness and six layers of x-y axis material on thebottom. The z-axis fiber deposition method described herein would beidentical, whether the material 30 was 100% x-y axis fiber material or asandwich material having a core and top 27 and bottom 29 “skin”material.

The key elements of the z-axis fiber deposition mechanism are shown inFIG. 1, although all of the details of how certain mechanisms aresupported or actuated are not shown. The first step of the process hasthe material 30 being drawn into the chamber in the containment housingbetween upper and lower surfaces 20 and 21, respectfully. Material 30 isstopped because the machinery moves synchronously to the pultrusionspeed. This allows the “pathway deposition probe” (PDP) 35 to beinserted through the material 30. Alternatively, the material could bemoving continuously and the deposition process could be gantry andsynchronous with the pultrusion speed. The PDP 35 is an elongated solidrod having a tapered front tip, a shank portion, and a rear end. PDP 35is first rotated by a motor 50 and then actuated upwardly by way of anactuator 61.

Then the process begins in which a fiber bundle, shown by the singleline 7, is deposited in the stack of x-y axis material 30. Although thefiber bundle is shown as a single line, in fact it could be a glass,carbon, or other fiber bundle containing hundreds or even thousands ofcontinuous fiber filaments. This process will be referred to as thez-axis fiber deposition process. The z-axis fiber bundle 7 is containedon a stationary roll 5 which is free to be drawn continuously from theroll 5. The fiber bundle is fed through a guidance bushing 10 andthrough two tubes, one of which is stationary outer tube 15 and theother a movable tube 16. Stationary outer tube 15 and movable inner tube16 are concentric with very close tolerances and are both penetrated attwo locations to accept a fiber clamp 12A and a fiber clamp 12B. Fiberclamp 12A is by definition, stationary, as it penetrates the stationaryouter tube 15. Fiber clamp 12B is by definition, movable, as it mustmove with the movement of the mechanism in the z-axis direction of themoveable inner tube 16. Moveable fiber clamp I2B may or may not beextended when tube 16 is moving. The actuation mechanism of clamp 12B isindependent of the actuation mechanism for tube 16, both of which areshown in FIG. 1 for clarity. The purpose of fiber clamps 12A and 12B isto provide positive clamping of the fiber bundle to the interior oftubes 15 and 16, respectively, at different times and for differentpurposes.

Once the PDP 35 has rotated, has been actuated in the z-axis direction,and has fully penetrated the x-y axis fiber layers 30, the PDP 35 is notyet touching the outer movable tube 16, but has passed completelythrough material 30. At this time, the PDP 35 has stopped rotating.

As mentioned previously, the rotation of PDP 35 assists in thepenetration of material 30 with minimum force and minimum fiber damagein the x-y axis material 30. The next step in the process is as follows:fiber clamp 12A is unclamped and fiber clamp 12B is clamped. Byactuating fiber clamp 12B, in the clamped location, fiber bundle 7 issecured to the inner wall of moveable tube 16 and allows fiber bundle 7to move with tube 16. In an alternative embodiment, the fiber bundle 7may not be secured to the moveable tube 16 when the tube is moved intothe material 30. For example, but not by way of limitation, the PDP 35and tube 16 may first create a fiber bundle path in the material 30.Once the fiber bundle path is created, the fiber bundle 7 may beinserted into this fiber bundle path, preferably through the tube 17while the tube 17 is in the fiber bundle path. The tube 17 may then beremoved from the fiber bundle path, leaving the fiber bundle 7 in thefiber bundle path in the material 30. As the tube 17 is removed, thefiber bundle 7 may be retained by the PDP 35 or another retainingmechanism to prevent the fiber bundle 7 from accidentally being removedfrom the fiber bundle path with removal of the tube 17.

Once clamp 12B has secured the fiber bundle 7 to movable inner tube 16,a mechanism (not shown) moves inner tube 16 downward in the z-axisdirection until the bottom end of the tube 16 makes contact with theoutside of the PDP 35 (which has already penetrated the x-y axismaterial 30) but at this time is not rotating. Alternatively, themeeting of the tube 16 and PDP 35 may occur without the tube 16 and PDP35 making contact instead of the meeting of the tube 16 and PDP 35occurring with the tube 16 and PDP 35 making contact as described above.

Next, the mechanism that moves inner tube 16, moves fiber bundle 7 andthe PDP 35 through the entire x-y axis material 30. PDP 35 had created apathway for inner tube 16 to be inserted through material 30. A certainamount of low actuation force on the PDP 35 insures that the inner tube16 stays intimate and in contact with the PDP 35. This technique insuresa smooth entry of tube 16 and the clamped fiber bundle 7 through the x-yaxis material 30. Fiber bundle 7 is pulled off the spool 5 by thisprocess.

Next fiber clamp 12B is released into the unclamped position and fiberclamp I2A is actuated into a clamped position. In this way, fiber clamp12A secures fiber bundle 7 against the interior wall of stationary tube15. This ensures that the fiber bundle 7 remains stationary anddeposited in the x-y axis material 30. Following this, moveable innertube 16 is withdrawn from the x-y axis material 30 and actuated upwardlyin the z-axis direction back to the original position shown in FIG. 1.When this step is done fiber bundle 7 does not move. Fiber bundle 7remains as a fully deposited fiber bundle in the z-axis direction. Next,fiber bundle 7 is sheared off at the top of the x-y axis material 30 bya shear plate 25 and 26. The stationary part of shear plate 26 nevermoves. The movable portion 25 is actuated by an actuator 60. This cutsfiber bundle 7, much like a scissors cut, and allows the fiber bundle 7,which is carried by spool 5, to be separated from the z-axis fiberdeposited bundle (Alternatively, the z-axis fiber may be severed fromthe fiber bundle 7 prior to insertion instead of after insertion.). Thisallows a preparation for the second z-axis fiber deposition. Thepreparation includes adjusting the end of the fiber bundle 7 relative tothe end of shear plate 26. As shown in FIG. 1, the end of fiber bundle 7is drawn slightly inwardly from the bottom end of tube 16. This isnecessary to allow the point on the tip of PDP 35 to enter tube 16without fiber being caught between the contact points of inner tube 16and PDP 35. This is accomplished as follows:

Once sheer plate 25 has cut the deposited z-axis fiber from fiber bundle7, the end of fiber bundle 7 is slightly extended below the inner tube16. Next, fiber clamp 12A is released and fiber clamp 12B is actuatedand clamped. Inner tube 16 is actuated further upward in the z-axisdirection as shown in FIG. 1 until the end of fiber bundle 7 is in thesame relative position as that shown in FIG. 1. Next, clamp 12A isactuated and clamped and clamp 12B is released, unclamped. Followingthis, inner tube 16 is moved downward in the z-axis direction to theposition shown in FIG. 1, thus that the relative position of the end ofmoveable inner tube 16 and the end of fiber bundle 7 is as shown inFIG. 1. The cycle is now set to be repeated.

All of the previously described operation can occur rapidly. Severalunits of the device as illustrated in FIG. 1 are installed side-by-side.The movement of an entire housing containing all of the devices of FIG.1 occurs with the x-y axis material 30 and the plates 25 and 26remaining stationary. In this way, for example, while the material 30 isstopped, an extra z-axis fiber can be deposited between the locations oftwo z-axis fibers deposited on the first cycle. A high number of z-axisfiber bundles in one row, with material 30 stationary, can in fact bedeposited. Once a row, which is defined as the deposited z-axis fiberslineal in the y direction, is completed, material 30 can be movedrelative to the machinery of FIG. 1 and a second row of z-axis fiberscan be deposited. This new row can have the same pattern or a staggeredpattern, as required.

One other device in FIG. 1 requires mentioning. Spring 40, located atthe base PDP 35 and between the PDP and the motor 50 has a specialpurpose. When inner tube 16 contacts PDP 35, and then subsequentlypushes PDP 35 back through the layers of x-y axis material 30, a flaringin the end of the tube can occur, if the relative force between the twoexceeds a certain value. The flaring of the end of the tube 16 willresult in failure of the mechanism. Spring 40 prevents this excessdifferential force, thus resulting in no flaring of the end of tube 16.

Although the material 30 has been described as being within the x-yplane and the tube 16 and PDP 35 moving in the z direction,alternatively, the method may include the material 30 moving in the zdirection for providing the z-axis reinforcing fiber into the material30 instead of or in addition to the tube 16 and PDP 35 moving in the zdirection. For example, the method may include providing an elongatedpathway deposition device 35 in close proximity to one of the top orbottom surfaces of the material 30; providing an elongated z-axis fiberinsertion element 16 in close proximity to the other of the top orbottom surfaces of the material 30; providing a z-axis reinforcing fiberbundle 7 into the z-axis fiber insertion element 16; moving the material30 so that the pathway deposition device 35 is provided into and throughthe material 30 a predetermined distance; moving at least one of thez-axis fiber insertion element 16 and the pathway deposition device 35in the z-axis direction so that the front end of the z-axis fiberinsertion element 16 and the tip of the pathway deposition device meet35; moving the material 30 so that z-axis reinforcing fiber bundle 7 andthe z-axis fiber insertion element 16 are disposed through the entirethickness of the material 30; separating the z-axis fiber insertionelement 16 and the material 30, thus causing the z-axis reinforcingfiber bundle 7 to remain within the material 30; and severing the z-axisreinforcing fiber that is within the material 30 from the z-axisreinforcing fiber bundle 7.

FIG. 2 is a schematic side elevation view of the z-axis fiber depositionmachinery integrated with the pultrusion process. The 2-D layers of x-yaxis material 30 are stored on rolls 70. They are pulled through a resintank 31 where the 2D material is impregnated with resin. They are thenpulled through debulking bushings 72 where, sequentially, the plies arestacked and each succeeding bushing 72 squeezes progressively a littlemore resin out of the stack of x-y axis material 30 as the x-y axismaterial 30 progresses toward the z-axis fiber deposition machine 73.Once through machine 73, the 3-D fiber composite material, nowidentified as numeral 31 since it has z-axis fibers deposited in it,progresses to pultrusion die 74. Here a heated die 74 cures the 3-Dfiber composite material 31 on the fly, and it exits the die 74 as cured3D fiber composite material 32. The material 32 is pulled from the die74 continuously by the alternate gripping action of two grippers 75 thatare attached to motion control hydraulic cylinders 76. Cylinders 76 areCNC type cylinders and can accurately position and time the material 30for z-axis deposition.

Although the x-y material 30 has be described as being impregnated withresin prior to the insertion of 3-D fiber, with reference to FIG. 7, theresin tank 71 may be located down-line from the z-axis fiber depositionmachine 73 so that 3-D composite fiber material 31 is impregnated withresin after the insertion of 3-D fiber. Alternatively, the x-y material30 may be impregnated with “pre-preg” resin at the factory where the x-ymaterial 30 was made and/or the 3-D fiber material was made. In thiscase, no resin impregnation would be needed in the process, eitherbefore or after the insertion of the 3-D fiber material.

An alternative to the feed mechanism described earlier in FIG. 1 anddepicted by clamps 12A and I2B, and the outer tube 15 and inner tube 16,can be replaced by the feed mechanism illustrated in FIG. 3. This feedmechanism requires a more sophisticated motion control than the clampsystem of FIG. 1, as will be evident in the description below.

The components of FIG. 3 shown above the carrier plate 20 replace thecomponents of FIG. 1 shown above the carrier plate 20. The key newcomponents are a tube 16, a urethane reel 19, an idler bearing 18, aspring 17, a drive belt 22 and a CNC type motion control motor 23. Allof these components are intimately connected to a frame (not shown),which is driven through carrier plates 20 and 21, by a CNC-type motorand ball screw (also not shown). In this way, all of the components 16,19, 18, 17, 22 and 23 move together as a synchronous unit.

The embodiment illustrated in FIG. 3 has the same fiber roll 5, fibertow or bundle 7, and guidance bushing 10. Idler bearing 18 and urethanewheel 19 provide a positive clamping of the fiber bundle 7. Spring 17,assures a side force of known quantity and clamps the fiber bundle 7.When motion control motor 23 is in a locked position, not rotated, fiberbundle 7 is clamped and cannot be moved. When motor 23 is rotated, fiberbundle 7 moves relative to tube 16, since the position of tube 16 isalways the same as the other components 19, 18, 17, 22 and 23 of FIG. 3.In this way, fiber bundle 7 can either be clamped so that it can notmove inside tube 16 or it can be moved inside tube 16 by rotation of themotion control motor 23.

It should now be apparent that the mechanisms illustrated in FIG. 3 cansubstitute for those identified in FIG. 1. When tube 16, with fiberbundle 7 clamped, is moved by a CNC motor (not shown) through the x-yaxis material 30, motor 23 is not rotated. However, when tube 16 isdrawn from the x-y axis material 30, motor 23 is rotated at the exactrate of speed as the withdraw of PDP 35. This can be accomplished withpresent day sophisticated motion control hardware and software. In doingthis, fiber bundle 7, stays stationary relative to x-y axis material 30,even though tube 16 is being withdrawn.

The advantage of the mechanisms in FIG. 3, although they provideidentical functions to their counterparts in FIG. 1, is that the speedof the process can improve by eliminating the alternative clamping ofclamps 12A and 12B. Nevertheless, either set of mechanisms is viable forthe disclosed invention.

FIG. 8 is a schematic side elevation view of another embodiment of afiber deposition unit where fibers 7 are deposited in the x-y compositematerial 30 in the z-x/y direction. As used herein, z-x/y directionreinforcing fiber or depositing fiber 7 in the z-x/y direction meansthat the fiber 7 may be deposited in the x-y material 30 in the z-xdirection, in the z-y direction, or the z-x-y direction. The fiberdeposition unit illustrated in FIG. 8 is similar to the z-axis fiberdeposition unit described above with respect to FIG. 3 except the fiberdeposition equipment located above the x-y composite material 30 (e.g.,tube 16, urethane reel 19, idler bearing 18, spring 17, drive belt 22,CNC type motion control motor 23) is generally offset along the xdirection (or the y direction or both the x and y direction) withrespect to the fiber deposition equipment located below the x-ycomposite material (e.g., PDP 35, spring 40, motor 50, actuator 61).Further, some of the fiber deposition unit equipment is disposed at anangle in the z-x/y direction (e.g., tube 16 with fiber 7, PDP 35).Deposition of the fibers 7 in the x-y material 30 occurs in the samemanner as that described above with respect to FIG. 3, except the fibers7 are deposited at an angle in the x-y material 30 in the z-x/ydirection (i.e., through the one or more layers of the x-y material, butnot perpendicular to the z axis). Orienting the fibers 7 at an angle inthe z-x/y direction in the x-y material 30 not only reinforces thestrength of the composite material in the z direction, but increases theshear strength, shear modulus, moment of inertia of the compositematerial. This makes the resulting composite ideal for applicationsrequiring flexural stiffness and shear stiffness.

1. A method of inserting a z-axis reinforcing fiber into a compositelaminate for z-axis reinforcement of the composite laminate comprising:providing at least one layer of material made up of x-axis fibers andy-axis fibers prior to incorporation of a z-axis reinforcing fiber intosaid at least one layer of material; said at least one layer having atop surface, a bottom surface and a predetermined thickness; providingan elongated pathway deposition device having a front tip, a shankportion, a rear end and a z-axis and positioning said front tip of saidpathway deposition device in close proximity to one of said top orbottom surfaces of said at least one layer of material; providing anelongated moveable z-axis fiber insertion element having a front end, arear end, an inner wall surface and a z-axis; positioning said front endof said moveable z-axis fiber insertion element in close proximity tosaid other of said top or bottom surfaces of said at least one layer ofmaterial; providing a z-axis reinforcing fiber bundle having a front endand inserting said front end of said z-axis reinforcing fiber bundleinto said rear end of said moveable z-axis fiber insertion element untilit travels substantially to said front end of said moveable z-axis fiberinsertion element; inserting said pathway deposition device into andthrough said at least one layer of material a predetermined distance;temporarily securing said z-axis reinforcing fiber bundle to said innerwall of said z-axis fiber insertion element so that said z-axisreinforcing fiber bundle will move with said z-axis fiber insertionelement; moving said z-axis fiber insertion element in the z-axisdirection until said front end of said z-axis fiber insertion elementmeets with the tip of said pathway deposition device; moving said z-axisfiber insertion element and said z-axis reinforcing fiber bundle securedthereto through the entire thickness of said at least one layer ofmaterial while at the same time withdrawing said pathway depositiondevice from said at least one layer of material; unsecuring said z-axisreinforcing fiber bundle from said inner wall of said z-axis fiberinsertion element and then withdrawing said z-axis fiber insertionelement from said at least one layer of material, thus causing saidz-axis reinforcing fiber bundle to remain within said at least one layerof material as said z-axis fiber insertion element is withdrawn; andsevering the z-axis reinforcing fiber that is within said at least onelayer of material from said z-axis reinforcing fiber bundle.
 2. A methodas recited in claim 1 wherein said pathway deposition device is spinningduring insertion into said at least one layer of material.
 3. A methodas recited in claim 1 further comprising stepping said said at least onelayer of material forwardly so that the previous steps can be repeatedin order to deposit additional z-axis reinforcing fiber into said atleast one layer of material.
 4. A method as recited in claim 3 whereinsaid at least one layer of material is first moved forwardly and thenmade stationary in order to deposit additional z-axis reinforcing fiberinto said at least one layer of material.
 5. A method as recited inclaim 3 wherein the stepping of said at least one layer of materialforwardly and the depositing of said additional z-axis reinforcing fiberinto said at least one layer of material is done synchronously.
 6. Amethod as recited in claim 1 further comprising stepping rearwardly themachinery that performs the operations of inserting a z-axis reinforcingfiber into a composite laminate for z-axis reinforcement; said at leastone layer of material would remain stationary.
 7. A method as recited inclaim 1 further comprising the step of passing said at least one layerof material with its newly inserted z-axis reinforcing fibers through apultrusion die for curing composite material.
 8. A method as recited inclaim 1 further comprising multiple layers of material stacked upon eachother and into which z-axis reinforcing fiber are inserted.
 9. A methodas recited in claim 8 in which some of said layers of material arevertically spaced from each other by a core layer of material.
 10. Amethod as recited in claim 9 wherein said core layer of material is madeof at least one of foam plastic and polyisocyanurate foam.
 11. A methodas recited in claim 9 wherein said core layer of material is made ofbalsa wood.
 12. A method as recited in claim 9 wherein said core layerof material is made of honeycomb material.
 13. A method as recited inclaim 1 wherein said z-axis reinforcing fiber bundle is made of glassfibers.
 14. A method as recited in claim 1 wherein said z-axisreinforcing fiber bundle is made of carbon fibers.
 15. A method asrecited in claim 1 wherein said z-axis reinforcing fiber bundle is madeof aramid fibers.
 16. A method as recited in claim 1 wherein said rearend of said pathway deposition device has a dampening spring to preventflaring of said front end of said z-axis fiber insertion element.
 17. Amethod of providing a z-axis reinforcing fiber into a composite laminatefor z-axis reinforcement of the composite laminate comprising: providingat least one layer of material made up of x-axis fibers and y-axisfibers prior to incorporation of a z-axis reinforcing fiber into said atleast one layer of material; said at least one layer having a topsurface, a bottom surface and a predetermined thickness; providing anelongated pathway deposition device having a front tip, a shank portion,a rear end and a z-axis and providing said front tip of said pathwaydeposition device in close proximity to one of said top or bottomsurfaces of said at least one layer of material; providing an elongatedz-axis fiber insertion element having a front end, a rear end, an innerwall surface and a z-axis and providing said front end of said moveablez-axis fiber insertion element in close proximity to said other of saidtop or bottom surfaces of said at least one layer of material; providinga z-axis reinforcing fiber bundle having a front end and inserting saidfront end of said z-axis reinforcing fiber bundle into said rear end ofsaid z-axis fiber insertion element until it travels substantially tosaid front end of said z-axis fiber insertion element; moving said atleast one layer of material so tat said pathway deposition device isprovided into and through said at least one layer of material apredetermined distance; moving at least one of said z-axis fiberinsertion element and said pathway deposition device in the z-axisdirection so that said front end of said z-axis fiber insertion elementand said tip of said pathway deposition device meet; moving said atleast one layer of material so that z-axis reinforcing fiber bundle andsaid z-axis fiber insertion element are disposed through the entirethickness of said at least one layer of material; separating said z-axisfiber insertion element and said at least one layer of material, thuscausing said z-axis reinforcing fiber bundle to remain within said atleast one layer of material; severing the z-axis reinforcing fiber thatis within said at least one layer of material from said z-axisreinforcing fiber bundle.
 18. A method of inserting a z-axis reinforcingfiber into a composite laminate for z-axis reinforcement of thecomposite laminate comprising: providing at least one layer of compositelaminate material prior to incorporation of a z-axis reinforcing fiberinto said at least one layer of material; said at least one layer havinga top surface, a bottom surface and a predetermined thickness; providingan elongated pathway deposition device having a front tip, a bodyportion, a rear end and a z-axis and providing said front tip of saidpathway deposition device in close proximity to one of said top orbottom surfaces of said at least one layer of material; providing anelongated moveable z-axis fiber insertion element having a front end, arear end, and a z-axis and providing said front end of said moveablez-axis fiber insertion element in close proximity to said other of saidtop or bottom surfaces of said at least one layer of material; providinga z-axis reinforcing fiber bundle in said moveable z-axis fiberinsertion element; inserting said pathway deposition device into andthrough said at least one layer of material a predetermined distance;moving at least one of said pathway deposition device and said z-axisfiber insertion element in the z-axis direction until said front end ofsaid z-axis fiber insertion element meets with the tip of said pathwaydeposition device; and moving said z-axis fiber insertion element andsaid z-axis reinforcing fiber bundle through the entire thickness ofsaid at least one layer of material while at the same time withdrawingsaid pathway deposition device from said at least one layer of material;withdrawing said z-axis fiber insertion element from said at least onelayer of material, thus causing said z-axis reinforcing fiber bundle toremain within said at least one layer of material as said z-axis fiberinsertion element is withdrawn; severing the z-axis reinforcing fiberfrom said z-axis reinforcing fiber bundle.
 19. A method as recited inclaim 18, wherein said least one layer of material is made up of x-axisfibers and y-axis fibers.
 20. A method as recited in claim 18, whereinsaid least one layer of material is made up of rovings.